Improved measurement of the head-tail effect in nuclear recoils

TL;DR

This paper reports on improved methods for measuring the head-tail effect in nuclear recoils, using a prototype detector to determine the direction of incoming particles relevant for dark matter detection.

Contribution

The study introduces a new measurement technique with a prototype detector that enhances the accuracy of head-tail determination in nuclear recoils for dark matter searches.

Findings

Successful imaging of recoil tracks in a low-pressure TPC

Effective ionization rate measurement along recoil trajectories

Enhanced capability to determine recoil direction tags

Abstract

We present new results with a prototype detector that is being developed by the DMTPC collaboration for the measurement of the direction tag (head-tail) of dark matter wind. We use neutrons from a Cf-252 source to create low-momentum nuclear recoils in elastic scattering with the residual gas nuclei. The recoil track is imaged in low-pressure time-projection chamber with optical readout. We measure the ionization rate along the recoil trajectory, which allows us to determine the direction tag of the incoming neutrons.